A helicopter flies behind a poster of Supreme Leader Ali Khamenei in Tehran.… (Vahid Salemi, AP )
WASHINGTON — Though initially skeptical that top Iranian regime figures were behind a plot to assassinate Saudi Arabia's ambassador to Washington, U.S. government officials became convinced by the operation's money trail and now consider it likely that Iran's supreme leader was aware of the plan.
"This is the kind of operation -- the assassination of a diplomat on foreign soil -- that would have been vetted at the highest levels of the Iranian government," said a senior U.S. official who spoke on condition of anonymity because he was not authorized to speak publicly about sensitive analyses. "We can't prove that, but we do not think it was a rogue operation in any way."
Law enforcement and intelligence officials penetrated the alleged plot from the start. But American officials said Wednesday that what persuaded them they were tracking something much more than just idle talk between an Iranian American used-car salesman and a Drug Enforcement Administration informant was the transfer of $100,000 from Iran in July and August as a down payment to set the assassination in motion.
It became clear, they said, that the plan was being orchestrated by the Quds Force, a secretive unit of Iran's military.
"It's very difficult to explain that transfer, which also aligned perfectly with what the informant was telling us, any other way," the senior official said Wednesday.
Officials also said the U.S. picked up other intelligence that indicated the existence of the plot. Sen. Dianne Feinstein (D-Calif.) said after a Senate Intelligence Committee briefing that human and signals intelligence had played a role in unraveling the plot.
Feinstein also said that "the intelligence indicates there may be problems elsewhere," adding that there could be threats to Saudi, Israeli or American ambassadors in other countries. "There may be a chain of these things," she told reporters.
Iran has condemned the allegations as false and "politically motivated," the foreign ministry said in a statement.
Iran has a complex government system in which different arms of the regime are often in bitter conflict with each other. U.S. officials say the Quds Force, a branch of the Revolutionary Guard, supplies arms and training to insurgents who have killed American troops in Iraq and carries out covert operations, including assassinations. The Quds Force reports directly to Supreme Leader Ali Khamenei, U.S. officials believe.
Khamenei has been in an increasingly tense power struggle with Iranian President Mahmoud Ahmadinejad, who, U.S. analysts believe, has little control over large parts of the nation's security forces. Officials believe that Ahmadinejad and Iran's intelligence service were probably not briefed on the Saudi assassination plot, the officials said.
Iran experts outside the government have questioned whether the regime would have condoned what U.S. officials acknowledge was an amateurish plot, which allegedly began when the car salesman, Texas resident Manssor Arbabsiar, contacted the aunt of a man he thought might be a Mexican drug cartel operative. The alleged conspiracy, as detailed in a FBI criminal complaint, seemed surprisingly sloppy and risky for the Quds Force, which has a reputation for deadly competence, experts said.
"I'm scratching my head over this," said Greg Thielmann, a former State Department and congressional intelligence analyst. "It just doesn't make sense."
Rasool Nafisi, an Iranian American scholar who has written about the military, noted that in Iranian attacks on U.S. troops in Iraq, "They have shown they can be pretty crafty, and leave no fingerprints behind."
The nongovernmental analysts noted that an attack on U.S. soil would dramatically escalate Iran's confrontation with the U.S. They questioned why the Iranians would seek to hire an agent they didn't know well and why they would risk wiring money from Iran to pay him, knowing that such transactions are easily monitored.
U.S. diplomats faced some of the same sorts of questions as they began making the case Wednesday that other nations should condemn Iran's role in the plot and add new penalties to the many sanctions already in place.
Susan Rice, U.S. ambassador to the United Nations, met individually with members of the U.N. Security Council in hopes of convincing the body to unite in opposition to Iran's action.
But some countries wanted proof the plot was ordered by the regime. A European Union official said the plot would have "grave" consequences -- "if the allegations are confirmed."
Nicholas Burns, the veteran U.S. diplomat and point man for the Bush administration on Iran, said it would be difficult for the administration to win support for tough measures, especially given the resistance of China and Russia to sanctions on Iran.